define(function(require, exports, module) {
  'use strict';

  require('core');

  var $ = window.Zepto;
  var UI = $.AMUI;

  var Progress = (function() {
    /**
     * NProgress (c) 2013, Rico Sta. Cruz
     * @via http://ricostacruz.com/nprogress
     */

    var NProgress = {};
    var $html = $('html');

    NProgress.version = '0.1.6';

    var Settings = NProgress.settings = {
      minimum: 0.08,
      easing: 'ease',
      positionUsing: '',
      speed: 200,
      trickle: true,
      trickleRate: 0.02,
      trickleSpeed: 800,
      showSpinner: true,
      parent: 'body',
      barSelector: '[role="nprogress-bar"]',
      spinnerSelector: '[role="nprogress-spinner"]',
      template: '<div class="nprogress-bar" role="nprogress-bar">' +
          '<div class="nprogress-peg"></div></div>' +
          '<div class="nprogress-spinner" role="nprogress-spinner">' +
          '<div class="nprogress-spinner-icon"></div></div>'
    };

    /**
     * Updates configuration.
     *
     *     NProgress.configure({
   *       minimum: 0.1
   *     });
     */
    NProgress.configure = function(options) {
      var key, value;
      for (key in options) {
        value = options[key];
        if (value !== undefined && options.hasOwnProperty(key)) Settings[key] = value;
      }

      return this;
    };

    /**
     * Last number.
     */

    NProgress.status = null;

    /**
     * Sets the progress bar status, where `n` is a number from `0.0` to `1.0`.
     *
     *     NProgress.set(0.4);
     *     NProgress.set(1.0);
     */

    NProgress.set = function(n) {
      var started = NProgress.isStarted();

      n = clamp(n, Settings.minimum, 1);
      NProgress.status = (n === 1 ? null : n);

      var progress = NProgress.render(!started),
          bar = progress.querySelector(Settings.barSelector),
          speed = Settings.speed,
          ease = Settings.easing;

      progress.offsetWidth;
      /* Repaint */

      queue(function(next) {
        // Set positionUsing if it hasn't already been set
        if (Settings.positionUsing === '') Settings.positionUsing = NProgress.getPositioningCSS();

        // Add transition
        css(bar, barPositionCSS(n, speed, ease));

        if (n === 1) {
          // Fade out
          css(progress, {
            transition: 'none',
            opacity: 1
          });
          progress.offsetWidth;
          /* Repaint */

          setTimeout(function() {
            css(progress, {
              transition: 'all ' + speed + 'ms linear',
              opacity: 0
            });
            setTimeout(function() {
              NProgress.remove();
              next();
            }, speed);
          }, speed);
        } else {
          setTimeout(next, speed);
        }
      });

      return this;
    };

    NProgress.isStarted = function() {
      return typeof NProgress.status === 'number';
    };

    /**
     * Shows the progress bar.
     * This is the same as setting the status to 0%, except that it doesn't go backwards.
     *
     *     NProgress.start();
     *
     */
    NProgress.start = function() {
      if (!NProgress.status) NProgress.set(0);

      var work = function() {
        setTimeout(function() {
          if (!NProgress.status) return;
          NProgress.trickle();
          work();
        }, Settings.trickleSpeed);
      };

      if (Settings.trickle) work();

      return this;
    };

    /**
     * Hides the progress bar.
     * This is the *sort of* the same as setting the status to 100%, with the
     * difference being `done()` makes some placebo effect of some realistic motion.
     *
     *     NProgress.done();
     *
     * If `true` is passed, it will show the progress bar even if its hidden.
     *
     *     NProgress.done(true);
     */

    NProgress.done = function(force) {
      if (!force && !NProgress.status) return this;

      return NProgress.inc(0.3 + 0.5 * Math.random()).set(1);
    };

    /**
     * Increments by a random amount.
     */

    NProgress.inc = function(amount) {
      var n = NProgress.status;

      if (!n) {
        return NProgress.start();
      } else {
        if (typeof amount !== 'number') {
          amount = (1 - n) * clamp(Math.random() * n, 0.1, 0.95);
        }

        n = clamp(n + amount, 0, 0.994);
        return NProgress.set(n);
      }
    };

    NProgress.trickle = function() {
      return NProgress.inc(Math.random() * Settings.trickleRate);
    };


    /**
     * (Internal) renders the progress bar markup based on the `template`
     * setting.
     */

    NProgress.render = function(fromStart) {
      if (NProgress.isRendered()) return document.getElementById('nprogress');

      $html.addClass('nprogress-busy');

      var progress = document.createElement('div');
      progress.id = 'nprogress';
      progress.innerHTML = Settings.template;

      var bar = progress.querySelector(Settings.barSelector),
          perc = fromStart ? '-100' : toBarPerc(NProgress.status || 0),
          parent = document.querySelector(Settings.parent),
          spinner;

      css(bar, {
        transition: 'all 0 linear',
        transform: 'translate3d(' + perc + '%,0,0)'
      });

      if (!Settings.showSpinner) {
        spinner = progress.querySelector(Settings.spinnerSelector);
        spinner && $(spinner).remove();
      }

      if (parent != document.body) {
        $(parent).addClass('nprogress-custom-parent');
      }

      parent.appendChild(progress);
      return progress;
    };

    /**
     * Removes the element. Opposite of render().
     */

    NProgress.remove = function() {
      $html.removeClass('nprogress-busy');
      $(Settings.parent).removeClass('nprogress-custom-parent');

      var progress = document.getElementById('nprogress');
      progress && $(progress).remove();
    };

    /**
     * Checks if the progress bar is rendered.
     */

    NProgress.isRendered = function() {
      return !!document.getElementById('nprogress');
    };

    /**
     * Determine which positioning CSS rule to use.
     */

    NProgress.getPositioningCSS = function() {
      // Sniff on document.body.style
      var bodyStyle = document.body.style;

      // Sniff prefixes
      var vendorPrefix = ('WebkitTransform' in bodyStyle) ? 'Webkit' :
          ('MozTransform' in bodyStyle) ? 'Moz' :
              ('msTransform' in bodyStyle) ? 'ms' :
                  ('OTransform' in bodyStyle) ? 'O' : '';

      if (vendorPrefix + 'Perspective' in bodyStyle) {
        // Modern browsers with 3D support, e.g. Webkit, IE10
        return 'translate3d';
      } else if (vendorPrefix + 'Transform' in bodyStyle) {
        // Browsers without 3D support, e.g. IE9
        return 'translate';
      } else {
        // Browsers without translate() support, e.g. IE7-8
        return 'margin';
      }
    };

    /**
     * Helpers
     */

    function clamp(n, min, max) {
      if (n < min) return min;
      if (n > max) return max;
      return n;
    }

    /**
     * (Internal) converts a percentage (`0..1`) to a bar translateX
     * percentage (`-100%..0%`).
     */

    function toBarPerc(n) {
      return (-1 + n) * 100;
    }


    /**
     * (Internal) returns the correct CSS for changing the bar's
     * position given an n percentage, and speed and ease from Settings
     */

    function barPositionCSS(n, speed, ease) {
      var barCSS;

      if (Settings.positionUsing === 'translate3d') {
        barCSS = { transform: 'translate3d(' + toBarPerc(n) + '%,0,0)' };
      } else if (Settings.positionUsing === 'translate') {
        barCSS = { transform: 'translate(' + toBarPerc(n) + '%,0)' };
      } else {
        barCSS = { 'margin-left': toBarPerc(n) + '%' };
      }

      barCSS.transition = 'all ' + speed + 'ms ' + ease;

      return barCSS;
    }


    /**
     * (Internal) Queues a function to be executed.
     */

    var queue = (function() {
      var pending = [];

      function next() {
        var fn = pending.shift();
        if (fn) {
          fn(next);
        }
      }

      return function(fn) {
        pending.push(fn);
        if (pending.length == 1) next();
      };
    })();


    /**
     * (Internal) Applies css properties to an element, similar to the jQuery
     * css method.
     *
     * While this helper does assist with vendor prefixed property names, it
     * does not perform any manipulation of values prior to setting styles.
     */

    var css = (function() {
      var cssPrefixes = [ 'Webkit', 'O', 'Moz', 'ms' ],
          cssProps = {};

      function camelCase(string) {
        return string.replace(/^-ms-/, 'ms-').replace(/-([\da-z])/gi, function(match, letter) {
          return letter.toUpperCase();
        });
      }

      function getVendorProp(name) {
        var style = document.body.style;
        if (name in style) return name;

        var i = cssPrefixes.length,
            capName = name.charAt(0).toUpperCase() + name.slice(1),
            vendorName;
        while (i--) {
          vendorName = cssPrefixes[i] + capName;
          if (vendorName in style) return vendorName;
        }

        return name;
      }

      function getStyleProp(name) {
        name = camelCase(name);
        return cssProps[name] || (cssProps[name] = getVendorProp(name));
      }

      function applyCss(element, prop, value) {
        prop = getStyleProp(prop);
        element.style[prop] = value;
      }

      return function(element, properties) {
        var args = arguments,
            prop,
            value;

        if (args.length == 2) {
          for (prop in properties) {
            value = properties[prop];
            if (value !== undefined && properties.hasOwnProperty(prop)) applyCss(element, prop, value);
          }
        } else {
          applyCss(element, args[1], args[2]);
        }
      }
    })();

    return NProgress;
  })();

  UI.progress = Progress;

  module.exports = Progress;
});
